1. Field of the Invention
The present invention relates to a method for fabricating a cosmetic cover for a prosthetic component, particularly cosmetic covers constructed from foam material.
2. Description of the Prior Art
Annually there are a large number of amputations, each resulting in the need for a prosthesis to replace the missing limb. The individual prosthetic components have few aesthetic qualities. For example, the prosthetic components of a prosthetic leg are designed to provide structure that is capable of supporting the body and to provide structure that is capable of mechanical movement as close to human movement as possible. Such structure may include metal tubes, mechanical joints, etc.
It is well known that resilient elastomeric materials may be formed around the mechanical parts of the prosthesis, for example the ankle and foot portion, while shaped foam sleeves may be mounted over the longer tubular portions of the prosthetic components to simulate a leg that matches the sound one. The inner surface of the foam sleeve closely fits around the prosthetic component, while the outer surface is shaped to correspond generally to the shape of the human limb.
The preparation of a foam sleeve for use as a cosmetic cover has long been a manual task. A prosthetic component is selected that is appropriate for the needs of the individual""s physical attributes. The interior cavity of the foam sleeve is carved by hand to receive the prosthetic component therein. Hand carving is a tedious and labor intensive task, with the sleeve frequently being loose and ill fitting. Once the interior has been carved the exterior of the sleeve may be carved and smoothed to the desired shape.
The patent issued to Schall et al., U.S. Pat. No. 5,880,964 discloses an automated method for fabricating a cosmetic cover for a prosthetic limb. Using this method the technician takes measurements of the prosthetic components and the socket with a digitizing tool after the prosthetic components and socket have been fitted to an individual. These measurements are forwarded to a CAD system that calculates the interior dimensions from the exterior dimensions previously measured. The dimensions are downloaded to a milling machine, and the milling machine separately carves two mating longitudinal halves of the cosmetic cover from two separate cover blanks. The two separate halves are then attached to one another to form the sleeve.
Hand carving is a manually intensive task which relies upon a considerable amount of trial and error to achieve a properly fitting sleeve. The Schall ""964 patent discloses an automated method that includes taking measurements directly from a prosthesis; however, measurements taken by a digitizing tool directly from the metallic prosthetic components are generally inaccurate and require considerable adjustment. Also, mounting a xe2x80x9ccarving blankxe2x80x9d in a milling machine in the normal manner results in cuts that are uneven and that are of poor quality.
It is clear that there is a need for a method of cutting the interior cavity and the exterior surface of a cosmetic cover that is fast and accurate.
The present invention relates to a method for fabricating a cosmetic cover for a prosthetic component, particularly cosmetic covers constructed from foam material. Most simply stated the steps of this method comprise the selection of a prosthetic component appropriate for the patient, collecting data regarding its shape, providing this data to a computer-controlled milling machine, and cutting a cavity in the foam blank to the proper shape and size.
Prosthetic components may be of many different shapes and sizes depending upon the particular use intended; that is, what portion of a patient""s limb will the component replace. For example, the patient may require a below the knee, above the knee, below the elbow or above the elbow prosthesis. Additionally, there are many different manufacturers of such components and each component has a different shape. To provide a tight fit, the exterior dimensions of the prosthetic component must be carefully measured and provided to a computer having Computer Aided Design (CAD) capability. The computer is programmed to manipulate the data into the format required by a computer-controlled milling machine. The exterior dimensions must be converted into the dimensions of an interior cavity sized to receive the prosthetic component. Those dimensions are then separated longitudinally into two parts to provide two longitudinal halves of that cavity. This data is then downloaded into a computer-controlled milling machine for cutting the cavity in a foam block.
The milling machine has a pair of longitudinally opposed rotatable shafts lying along the milling machine""s axis of rotation, and a foam block is mounted therebetween for rotation. The milling machine has a cutting head designed for movement toward and away from the axis of rotation and longitudinally parallel to the axis of rotation. The cutting head is controlled by a computer having the proper dimensions stored therein, so that the cutter, mounted in the cutting head, engages one side of the block cutting a portion of one-half of the interior cavity therein as the block rotates. As the block continues to rotate, the cutter engages the opposed side of the block to cut a portion of the other half of the interior cavity therein, creating indentations in both opposed sides of the block. The cutter is then advanced longitudinally along the block so that it may cut portions of the cavity with each rotation until the total cavity is cut in the opposed sides of the block. The block is then removed from the milling machine and cut in half longitudinally between the indentations. The two halves of the block are then attached to one another so that the perimeters of the indentations coincide and a cavity having the general shape of the prosthetic component is formed.
The invention accordingly comprises an article of manufacturer possessing the features, properties, and the relation to elements which will be exemplified in the article hereinafter described, and the scope of the invention will be indicated in the claims.